Many others have had to drop a considerable percentage of their body weight to lift in one of the new Olympic categories, most notably the Tokyo champions Chen Lijun from China and Maude Charron from Canada, and the 87 kilograms women’s world champion Solfrid Koanda from Norway.

None of those three, however, had to shrink their weight by 15.5 per cent, which Morrow did before posting her first qualifying total on Thursday, the opening day of the International Weightlifting Federation Grand Prix here in Havana, Cuba.

Morrow, 24, suffered a back problem two months after winning a Commonwealth Games bronze medal for England at 55kg last year, and has had to lose weight while training at only 60 per cent of her capabilities for much of the time.

"I was training at 58 kilos last year so after coming back from injury and losing nine kilos I’m happy to make a total here - but I’m an athlete so I always want more," Morrow said after breaking all three British records in the 49kg B Group on 75-97-172.

The back injury would need surgery for a permanent fix - “basically parts of my lower spine are too long for my body, but I’m not having surgery during Olympic qualification".

Morrow started losing weight in December when, because of her back problem, she was lifting only 35 to 45kg in training.

"I went overboard a bit at Christmas and New Year because I knew the next 18 months were going to be tough," she said.

"It has been hard but I was down to 51kg by March and I have a nutrition team who have really helped."

Morrow’s efforts put her in the top 30 in the rankings and left her third in the B Group behind two athletes from Dominican Republic, the triple Olympian Beatriz Piron and Dahiana Ortiz.

Piron, 28, made 86-105-191, which will probably be enough for a medal after the A Group has finished on Friday night, and Ortiz made 83-105-188.

The evening A Group on day one in Havana, the men’s 55kg, had only three entries and one of those was from North Korea, whose team has not shown up here.

Osmel Argote from host nation Cuba made 98-124-222 to win gold ahead of Jose Ical from Guatemala on 95-115-210.

Chen lost about 10 per cent of his body weight when he dropped from 67kg to 61kg for the Asian Championships in South Korea last month, where the Rio 2016 champion Ruslan Nurudinov from Uzbekistan was unable to cut from 109kg to the Olympic category of 102kg.

It was less extreme for the Tokyo 64kg champion Charron and 87kg world champion Koanda because they planned well ahead and competed several kilos below the limit in higher classes before dropping.

Charron is now in the 59kg rankings for Paris, and Koanda is due to make her first outing at the Olympic weight of 81kg here in Cuba on June 16.

By coincidence, one of the referees for Morrow’s session was Daniel Nsegna, an academic working on a PhD at ULB university in Brussels, on "incidence and consequences of a strategy for losing weight quickly" in weightlifting and other sports with weight categories.

The Belgian-Cameroonian dual national, who was a coach at the Cameroon Federation for 12 years and is now its technical director, highlighted the potential dangers of trying to cut weight too quickly, which can lead to injuries and a drop in performance.

"In all my life as a coach, athletes were trying to lose weight," he said before Morrow went out to lift.

“In Cameroon the strategy was more like a punishment - just stop eating.”

Nsegna, a former 69kg athlete who moved to Belgium in 2011 and returned to Cameroon to lead its team at the 2014 Commonwealth Games in Glasgow, has been researching the subject since 2016 and will publish his latest work this year.

He studied 50 weightlifters in his early work, looking for the consequences of rapid weight loss on strength, performance and body composition and is hoping to widen that number to 500 across a range of sports.

"We discovered that losing weight quickly does not work long-term, that after a week or 10 days the body automatically tries to restore weight rather than lose it," Nsegna said.

"Usually it does not work if you lose more than 1kg a month. 

"If you do it can cause damage to the body, you might suffer injuries, lose muscle and therefore strength, and that can also affect your technique."

Cutting weight quickly makes sense only in the week before a competition, after two weeks of transition from the long-term strategy, Nsegna said.

"As a scientist, I believe that some of what is happening is dangerous for an athlete’s health, going up and down in weight to improve their qualification chances.

"Scientifically, our body is like a cup, it can take only so much coffee and no more. 

"There are absolute limits and when you modify a body’s capacity to absorb, that’s when you have doping.

"Your body knows what weight it should be."

While many athletes have cut the kilos to find an Olympic weight category, others have gone up.

The Olympic 109kg champion Akbar Djuraev from Uzbekistan is now a super-heavyweight weighing about 18kg more than he did in Tokyo, for example. 

Then there is CJ Cummings from the United States, who arguably has made the biggest proportional weight change of all those trying to qualify for Paris.

Cummings, ninth at 73kg in Tokyo, his last international appearance, is due to lift here at 89kg on Wednesday - up 22 per cent in body weight.

In American Open competitions Cummings was twice over 80kg to lift in the 81kg class in 2021 and 2022, and in March this year he weighed 88.27kg for his first try in the Olympic 89kg category.